1. Field of the Invention
The present invention relates to a lever switch mainly mounted in the vicinity of a steering wheel of a vehicle for use in operating a head lamp, a turn signal lamp, and the like.
2. Background Art
Recently, a lever switch, mounted in the vicinity of a steering wheel of a vehicle and operated for, for example, changing the lighting range of a head lamp and blinking a turn signal lamp, has been increased in number. A technology about such a lever switch is disclosed in, for example, Japanese Patent Application Unexamined Publication No. 2005-129238.
Hereinafter, such a conventional lever switch is described.
FIG. 3 is a sectional view showing a conventional lever switch; and FIG. 4 is an exploded perspective view thereof. In these figures, outer lever 3 and inner lever 4, which are made of insulating resin, are disposed between upper case 1 and lower case 2, which are also made of insulating resin. Furthermore, cover 15 made of insulating resin is disposed so as to cover the lower surface of upper case 1. Outer lever 3 is mounted in inner lever 4 at the left end thereof and protrudes toward the right side at the right end thereof. Furthermore, outer lever 3 is mounted between upper case 1 and lower case 2 in a rockable manner with respect to a middle portion as a fulcrum in the back-and-forth direction and the upper-and-lower direction from a neutral position.
A conventional lever switch is provided with insulating resin pin 5 and coiled spring 6 so that a rocking operation of outer lever 3 and inner lever 4 is carried out with a click feeling. Pin 5 and somewhat bending spring 6 are accommodated in a left end of inner lever 4. Furthermore, pin 5 is brought into elastic contact with a concave and convex portion on the left inner side wall of upper case 1, thereby forming a click feeling means in the back-and-forth direction.
Note here that a click feeling means in the upper-and-lower direction is formed additionally by a cam and an elastic member (not shown), and the like, between outer lever 3 and inner lever 4. Thereby, a rocking operation of outer lever 3 is carried out with a click feeling also in the upper-and-lower direction.
Furthermore, a conventional lever switch further includes operating body 7, driving body 8 and sliding body 9, which are made of insulating resin. The upper end of operating body 7 is engaged with the lower surface of the left end of inner lever 4, and the upper end of driving body 8 is engaged with the side surface of outer lever 3. Furthermore, the upper end of sliding body 9 is engaged with the lower surface of driving body 8.
Furthermore, a conventional lever switch has wiring boards 10 and 11 having a plurality of wiring patterns on the upper and lower surfaces thereof. Wiring board 10 and wiring board 11 are electrically connected to each other with a lead wire (not shown) and the like. Connector 16 is packaged on wiring board 11. In particular, a plurality of fixed contacts 14 are formed on the upper surface of wiring board 10. A conventional lever switch includes movable contacts 12 and 13, made of electrically conductive metal thin plate, corresponding to these fixed contacts 14. One end of movable contact 12 is fitted to the lower surface of operating body 7. One end of movable contact 13 is fitted to the lower surface of sliding body 9. The other ends of somewhat bending movable contacts 12 and 13 are brought into elastic contact with the upper surface of wiring board 10 and fixed contact 14.
Furthermore, a lever (not shown) that is similar to outer lever 3 and inner lever 4 is mounted to the left side of upper case 1 so as to configure a lever switch.
The thus configured lever switch is mounted with outer lever 3 protruding in the lower part of a steering wheel in front of a driver's sheet in a vehicle. Furthermore, a lead wire (not shown) and the like is coupled to connector 16 and a plurality of fixed contacts 14 are electrically connected to an electric circuit (not shown) of a vehicle via the lead wire.
In the above-mentioned configuration, when a rocking operation of outer lever 3 is carried out in the back-and-forth direction, inner lever 4 is rocked with a click feeling by pin 5 and spring 6 in the back-and-forth direction. At the same time, operating body 7 engaged with the lower surface thereof moves in the back-and-forth direction. An end portion of movable contact 12 fitted to operating body 7 elastically slides on the upper surface of wiring board 10. Thus, movable contact 12 is brought into contact with fixed contact 14 corresponding to an operation angle, and electrical connection and disconnection with respect to a plurality of fixed contacts 14 is carried out via movable contact 12.
Then, an electric signal of this is output to the electric circuit of a vehicle. With such a configuration, for example, when a rocking operation of outer lever 3 is carried out in the back-and-forth direction at a predetermined angle, a turn signal lamp for indicating turning right or turning left blinks during the operation. When outer lever 3 is operated at a predetermined angle or more, the turn signal lamp in this direction blinks continuously.
Furthermore, when a rocking operation of outer lever 3 is carried out in the upper-and-lower direction, sliding body 9 moves in the left and right direction via driving body 8 and an end portion of movable contact 13 fitted to sliding body 9 elastically slides on the upper surface of wiring board 10. Thereby, movable contact 13 is brought into contact with fixed contact 14, and electrical connection and disconnection with respect to a plurality of fixed contacts 14 via movable contact 13 is carried out.
Then, an electric signal of this is output to the electric circuit of a vehicle. With such a configuration, for example, according to the direction or angle of the rocking operation, the lighting range of a head lamp is changed to a low position or a high position, or passing, or the like.
That is to say, in the above-mentioned conventional lever switch, when a rocking operation of outer lever 3 is carried out in the back-and-forth direction or the upper-and-lower direction, movable contacts 12 and 13 elastically slide on the upper surface of wiring board 10 and are brought into mechanical contact with fixed contacts 14 according to the operation. Furthermore, movable contacts 12 and 13 are electrically connected to any of the plurality of fixed contacts 14 selectively by the elastic contact force thereof. Then, in accordance with this, an electric circuit of a vehicle blinks a turn signal lamp or changes the lighting range of a head lamp.
Such a lever switch is used in a state in which it is installed in the vicinity of a steering wheel of a vehicle. Such an installation place includes relatively large amount of dust, gas, humidity, and the like, and at the same time, a lubricant and the like is applied to peripheral components.
Therefore, such lubricant, gas, dust, humidity, and the like, enter the inside of the switch and are attached to the contact surfaces of movable contacts 12 and 13 and fixed contacts 14, which may adversely affect electrical connection and disconnection of the contacts. In order to avoid such an inconvenience, in a conventional lever switch, in general, a movable portion of outer lever 3 is covered with a rubber cap, or an adhesive agent and a shielding material is applied to gaps of upper case 1, lower case 2 and cover 15 so as to seal the gaps so that the switch has a hermetically sealed structure.
Thus, in the above-mentioned conventional lever switch, it is necessary that a switch have a hermetically sealed structure for obtaining a stable electrical connection and disconnection between movable contacts 12 and 13 and fixed contacts 14. As a result, the number of components is increased and it takes a long time to construct a switch.